Stabilizing Skin-Barrier™ Micro-Emulsion in Water-Based Serums/Toners (Separation and Texture Issues)

The issues you are experiencing (phase separation, cloudiness, and stickiness/oiliness) are common when incorporating a micro-emulsion like Skin-Barrier™ (ID: 7564) into a low-viscosity, fully water-based formula (serum or toner).

Here is a breakdown of the problem and recommended solutions:

1. Understanding Skin-Barrier™ Solubility

• Nature of the Product: Skin-Barrier™ is a micro-emulsion (a type of oil-in-water dispersion) containing skin-mimicking lipids (Ceramide NP, Cholesterol, Squalane, various oils) stabilized by a natural emulsifier (Hydrogenated Lecithin).
• Solubility: The product description correctly states it is dispersible in water, meaning it forms a stable dispersion, but it is not truly water-soluble. This is why the formula becomes cloudy (translucent to semi-transparent) and why it requires stabilization to prevent the dispersed oil droplets from separating.
• Phase Separation: In a very thin, water-like formula (low viscosity), the dispersed oil droplets are not physically held in place and will eventually coalesce and separate (phase separation).

2. Recommended Solutions for Stability and Texture

The key to solving both the separation and the texture issues is to increase the viscosity of the water phase and eliminate the unnecessary external solubilizer.

A. Stabilize the Dispersion (Prevent Separation)

Instead of adding more solubilizers (which cause stickiness), you need to use a thickener or hydrocolloid to physically suspend the micro-emulsion droplets.

• For Serums (Slightly Thicker): Use a water-soluble polymer like Xanthan Gum (0.2-0.5%), Carbomer (0.1-0.3%), or a liquid polymer like Acrylates Copolymer (e.g., Sepiplus 400 or similar) to increase the viscosity. This increased viscosity will hold the Skin-Barrier™ particles in suspension, preventing separation.
• For Toners (Very Thin): Even a toner requires a minimal amount of viscosity to stabilize a dispersion. Try using a very low concentration of a polymer like Xanthan Gum (0.05-0.1%) or a natural gum to provide just enough body without feeling heavy.

B. Address Cloudiness and Texture (Stickiness/Oiliness)

• Eliminate the Solubilizer: The stickiness and increased oiliness are almost certainly caused by the extra solubilizer you added. Since Skin-Barrier™ is already a pre-stabilized micro-emulsion, adding a large amount of external surfactant (solubilizer) is counterproductive. By stabilizing the formula with a polymer (as above), you can remove the external solubilizer, which should resolve the stickiness and reduce the oily feel.
• Accept the Translucency: The product is described as a translucent liquid. When dispersed in water, the resulting formula will be cloudy or semi-transparent, not crystal clear. This is the expected appearance for a micro-emulsion containing oils.

3. Correct Mixing Procedure

Follow the manufacturer's instructions precisely, ensuring the stabilizing polymer is fully hydrated first.

1. Prepare the Water Phase: Mix water, humectants (like Glycerin), and the chosen stabilizing polymer (e.g., Xanthan Gum). Mix until the polymer is fully hydrated and the water phase has the desired viscosity.
2. Check Temperature: Ensure the water phase temperature is below 40°C.
3. Add Skin-Barrier™: Slowly add the required amount of Skin-Barrier™ (1-15%) to the stabilized water phase while stirring gently but continuously. Avoid high-shear mixing, which can destabilize the micro-emulsion.
4. Final Adjustments: Adjust the pH to the recommended range (2.5-7.0) if necessary.

By using a polymer to stabilize the dispersion, you can achieve a stable, non-separating formula without the need for extra solubilizers that cause stickiness.